NDA 2025
- Exam
- NDA
- Year
- 2025
- Subject
- Mathematics
- Chapter
- Basics of Mathematics
NDA 2025 · Mathematics · Basics of Mathematics
If p^x = q^y = r^z , where x , y and z are in GP, then consider the...
If , where , and are in GP, then consider the following statements:
I. , and are in AP.
II. , and are in GP.
Which of the statements given above is/are correct?
I. , and are in AP.
II. , and are in GP.
Which of the statements given above is/are correct?
Options
- AI only
- BII only
- CBoth I and II
- DNeither I nor II
Correct answer
B. II only
Step-by-step solution
Let
Taking natural logarithm on all sides:
, ,
Since , , and are in GP,
Substituting the values of , , and :
\left( \dfrac{\ln k}{\ln q} \right)^2 = \left( \dfrac{\ln k}{\ln p} \right)\left( \dfrac{\ln k}{\ln r} \right)\dfrac{1}{(\ln q)^2} = \dfrac{1}{\ln p \ln r}(\ln q)^2 = \ln p \ln r\ln p\ln q\ln r$ are in GP.
Statement II is correct, while Statement I is not necessarily true.
Answer: II only
Taking natural logarithm on all sides:
, ,
Since , , and are in GP,
Substituting the values of , , and :
\left( \dfrac{\ln k}{\ln q} \right)^2 = \left( \dfrac{\ln k}{\ln p} \right)\left( \dfrac{\ln k}{\ln r} \right)\dfrac{1}{(\ln q)^2} = \dfrac{1}{\ln p \ln r}(\ln q)^2 = \ln p \ln r\ln p\ln q\ln r$ are in GP.
Statement II is correct, while Statement I is not necessarily true.
Answer: II only